Japanese Unexamined Patent Application Publication No. 2015-123843 discloses providing a vehicle capable of effectively using both of an electric motor connected to the same wheels as an internal combustion engine, and an electric motor connected different wheels from an internal combustion engine ([0006], Summary).
To this end, Japanese Unexamined Patent Application Publication No. 2015-123849 (Summary) describes a power control device 28 of a vehicle 10 that controls target vehicle power to be fulfilled by at least one of first electric motors 16 and 18 and an internal combustion engine 12, in a case where the target vehicle power is forward power and clutch units 38a and 38b (FIG. 1) are engaged. The power control device 28 also controls target vehicle power to be fulfilled by at least one of a second electric motor 14 and the internal combustion engine 12, in a case where the target vehicle power is forward power and clutch units 38a and 38b are disengaged.
The first electric motors 16 and 18 (rear-side motors 16 and 13) are connected to clutches 38a and 38b (FIG. 1) that are different front clutches 102, 104 (FIG. 2) of the internal combustion engine 12. The second electric motor 14(forward-side motor 14) is connected to the same clutch 102 as the internal combustion engine 12 (FIG. 2, [0035] through [0057]).
Japanese Unexamined Patent Application Publication No. 2015-123849 illustrates a partial-assist mode (S6 in FIG. 3, and FIGS. 4, 7, and 8) and a full-assist mode (S7 in FIG. 3, and FIGS. 4 through 6) as cases of the internal combustion engine 12 and the second electric motor 14generating traveling drive force at the same time. In full-assist mode, first assist motor switching processing (S14) is performed where assistance is switched from assistance by the rear-side motors 16 and 18 to assistance by the second electric motor 14 in a case where a vehicular speed V does not exceed a first vehicular speed threshold value THv1 (No in S11 in FIG. 5). It is stated that the determination. In step S11 may fee made by another indicator instead, as long as the rotations Nmot of the rear-side motor's 16 and 18 can be estimated ([0070]). The same holds true for the partial-assist mode as well (No in S21 in FIG. 7→S24). The reason that the rotations Nmot of the rear-side motors 16and 18 are made to serve as a reference for determination is stated to be to prevent excessive rotation of the rear-side motors 16 and 18 and so forth ([0100], [0104], [0107]).
Thus, Japanese Unexamined Patent Application Publication No. 2015-123849 describes the forward-side motor 14 being driven instead of the rear-side motors 16 and 18, to prevent excessive rotation of the rear-side motors 16 and 18 connected to the clutches 38a and 38b that are different from the clutches 102 and 104 of the internal combustion engine.